1.global __cp_begin
2.hidden __cp_begin
3.global __cp_end
4.hidden __cp_end
5.global __cp_cancel
6.hidden __cp_cancel
7.hidden __cancel
8.global __syscall_cp_asm
9.hidden __syscall_cp_asm
10
11#r0: volatile. may be modified during linkage.
12#r1: stack frame: 16 byte alignment.
13#r2: tls/thread pointer on pp32
14#r3,r4: return values, first args
15#r5-r10: args
16#r11-r12: volatile. may be modified during linkage
17#r13: "small data area" pointer
18#r14 - r30: local vars
19#r31: local or environment pointer
20
21#r1, r14-31: belong to the caller, must be saved and restored
22#r0, r3-r12, ctr, xer: volatile, not preserved
23#r0,r11,r12: may be altered by cross-module call,
24#"a func cannot depend on that these regs have the values placed by the caller"
25
26#the fields CR2,CR2,CR4 of the cond reg must be preserved
27#LR (link reg) shall contain the funcs return address
28 .text
29 .type __syscall_cp_asm,%function
30__syscall_cp_asm:
31 # at enter: r3 = pointer to self->cancel, r4: syscall no, r5: first arg, r6: 2nd, r7: 3rd, r8: 4th, r9: 5th, r10: 6th
32__cp_begin:
33 # r3 holds first argument, its a pointer to self->cancel.
34 # we must compare the dereferenced value with 0 and jump to __cancel if its not
35
36 lwz 0, 0(3) #deref pointer into r0
37
38 cmpwi cr7, 0, 0 #compare r0 with 0, store result in cr7.
39 beq+ cr7, 1f #jump to label 1 if r0 was 0
40
41 b __cp_cancel #else call cancel
421:
43 #ok, the cancel flag was not set
44 # syscall: number goes to r0, the rest 3-8
45 mr 0, 4 # put the system call number into r0
46 mr 3, 5 # Shift the arguments: arg1
47 mr 4, 6 # arg2
48 mr 5, 7 # arg3
49 mr 6, 8 # arg4
50 mr 7, 9 # arg5
51 mr 8, 10 # arg6
52 sc
53__cp_end:
54 bnslr+ # return if no summary overflow.
55 #else negate result.
56 neg 3, 3
57 blr
58__cp_cancel:
59 b __cancel